When the Isle of Armor and Crown Tundra were first announced for Pokemon Sword & Shield, it was revealed that the Slowpoke Evolution Chain would each be receiving a brand new Galarian Form. Little did Pokemon Fans know that the Slowpoke Evolution Chain would be the only Regular Pokemon Evolution Chain to be receiving such a thing. Because of this, players can only obtain two new Galarian Form Pokemon: Galarian Slowpoke and Galarian Slowbro.
When you first purchase the Pokemon Sword & Shield Expansion Pass, a mini event will occur at the Wedgehurst Train Station. There you will see a Galarian Slowpoke and will meet Klara (Sword) or Avery (Shield), ultimately being able to capture the Galarian Slowpoke. Once you reach the Isle of Armor, you will also notice a bunch of wild Galarian Slowpoke roaming free on the beach areas. Later in the Crown Tundra, you can find Galarian Slowpoke in Max Riad Battles. Suffice to say, Galarian Slowpoke is rather common and all players won't have any issues catching multiple of them should they so please.
Because Galarian Slowpoke is rather easy to obtain, it leaves the true question of how to evolve a Galarian Slowpoke into the Crown Tundra Exclusive Galarian Slowking. In order to obtain a Galarian Slowking, players will first have to search and find fifteen Galarica Twigs. These are also a pretty common item, found at the base of most trees in the Isle of Armor and Crown Tundra. Once you have fifteen Galarica Twigs, head to Roaring-Sea Caves via the Frigid Sea Entrance within the Crown Tundra. Here, you will find a young lady that will be willing to turn your fifteen Galarica Twigs into a Galarica Wreath. This is the item that players can use to evolve Galarian Slowpoke into Galarian Slowking simply by accessing it within their bag and having Galarian Slowpoke within their Party. It's as easy as that!